1. Field of the Invention
This invention relates to a transportable data input/output unit capable of being detached from the body of a numerical control device.
2. Description of the Related Art
In numerical control, there are cases where a host computer is used and made to perform a variety of data processing tasks to create command data for the machining of a workpiece. The data created by the host computer is recorded on a paper tape by a tape puncher and, with the paper tape serving as the recording medium, is used as input information for another system. In creating the paper tape, the contents of the tape are printed out by a printer in order to provide a record thereof beforehand. Where an output from the host computer is recorded on the paper tape or printed on recording paper, the paper tape puncher and printer used ordinarily are provided separately from the host computer body. These pieces of peripheral equipment are directly connected to the host computer and operate solely in response to commands therefrom. Unlike a system in which such peripheral equipment is of a disjointed nature, a system is conceivable in which the peripheral equipment operates on the basis of commands from a host computer when connected to the computer, but in which the contents of a paper tape may be read independently and printed for copying purposes when the peripheral equipment is disconnected from the host computer. However, a system such as this can be applied to only very limited systems and is inapplicable to others in certain aspects. Moreover, even where applicable, a disadvantage occurs in that results cannot be obtained unless the host computer software is modified. Furthermore, where numerical control data is to be dealt with, a parity code is sometimes added which will render the length of one block punched into a paper tape an even or odd number. Heretofore, with a paper tape having a parity code, copying the paper tape has meant copying the parity code as well. In cases where data recorded on such a paper tape are read into a numerical control device which does require a parity code, the parity code is meaningless information which has the deleterious effect of delaying data processing. Conversely, when a paper tape not furnished with a parity code is copied, providing the tape with a parity code is impossible when attempted.